Automatic telephone system.



D. S. HULFISH. AUTOMATIC TELEPHONE SYSTEM.

RENEWED JUNE 28,1915.

, APPLICATION FILED OCT-16, 19H. L,1'70,9'09.

Patented Feb. 8, 1 916. 2 SHEETSSHEET I w oooo oooo oooo ou o O n THB COLUMBIA PLANOGRAPH 60-. WASHINGTON, n. c.

D. S. HULFISH. AUTOMATIC TELEPHONE SYSTEM.

APPLICATION FILED 0CT.16, 1911. RENEWED JUNE 28,1915.

Patented Feb. 8, 19161 2 SHEETSSHEET 2.

ooooooo'ooooo oooo oooooooo ooooooooooo oooooooooooo oooooooo oooo oooooooooo o ooooooooooo oooooooo 0oo+oo0 nk JoooooooooobJoooo moooooooooo m om oo m ooooooooo obLoooo Jooocoooooobuoxfipo wwoeoooooooom uoqoo oooooooooom oYoo MO O O O O QIX-OMO Q oooo o M o T o o F o 0 0 o oooooooooomwcodo ooooooo oo oooo o ooooooooowwomo o 000000090 00000009009 oo ooo,oooooo o eoooooooocoo THE COLU'MBIA PLANORAPH (10., WASHINGTON, D. C.

UNITED ST ES PAT T OFFICE.

DAvID s. HULFISH, or TORONTO, ONTARIO, CANADA, ASSIGNOR To CANADIAN INDE- PENDENT TELEPHONE COMPANY, LIMITED, or TORONTO, oANADA, A CORPORATION OF CANADA.

Application filed October 16, 1911, Serial No. 654,872.

devices, and in which one of the acts of.

forming a connection between two lines is the connection automatically .of the c lling line and'a switching device. .4,

My invention comprises means for selecting an idle switching device and means for connecting it to a calling line.

My invention may be used with manual or automatic telephone switching and is de pendent of the switching system or type of switches used. I have shown it in the drawings as adapted forthefilhorimer system of automatic telephone switching.

I illustrate my invention applied to, a switch of two movements of select ong I. provide means for starting a prevlously sc lected' switch in one of its-,movements of selection, and means for stopping it when in that movement it has encountered the subgroup of the calling line; I provide means then operative for starting the switch in its second movement of selection, and means :for stopping it when in that movement it has encountered the calling line. I provide means'then operative for selecting another switch in readiness to respond to another calling line in the line group. i

The circuits and apparatus of my invention are illustrated in the accompanying drawings, two sheets containing four figures,

in which y I Figure 1 comprising the central and upper right-hand portion of the first sheet,

illustrates the apparatusof the relay and. terminal rack, Fig. 2 the. upper left-hand. portion of, the first sheet, illustrates thev essential parts of a substation telephone, Fig. 3 across the bottom of the first sheet,

illustrates the division starter and all apparatus common to the lines and connective divisions of a group, Fig. 4 comprising all:

ofthe second sheet, illustrates-the apparatus and circuits of those parts ofa connective- Specification of Letters Eatent.

AUTOMATIC TELEPHONE SYSTEM.

Patented Feb. 8, 1916.

Renewed June 28, 1915. Serial No. 36,915.

division of the Lorimer type involved in my invention and also the main battery, common to the entire central ofiice, and 5 shows a modification.

The two sheetsregister together to form a, larger figure for convenience in studying the circuits. i

. In the figures, numerals smaller than 100 are not reference labels within the ordinary mean ng of the term; they are numerals indicatlngthe order or relation of the parts ad acent to which they are found, as indicatmg the orderofcontact points in a row, or the order of rows in a contactba-nk; for example, the numeralsl to 18 in Fig.3 vare stamped upon the apparatus as built and used and form a part of the-apparatus illustrated .bygthe idrawing rather than labels referring to it. I

Reference numerals 101 to 199 have been reserved for conductors, 200 to 299 for apparatus parts, and 70.0 to 799 for directory numberspf the telephone lines of the group taken for illustration.

. Like numerals refer out ,thegfiguresr I :The group, of lines taken for illustration is the eighth group, or group N o. :7 ,containinglinesTOO' to 79 9, served by a group of connective divisions of which theifirst division, served bystarter points 12-3, is illustrated in Fig. 4, portions of other connective divisions being shown in Fig. 8.

A .Lorimer i switch of the cylinder type, with register, illustrated in Fig. 4. The horizontal rows of small circles represent the fixed contact points upon the developed inner surface of an annular casting of insulating material; upon these contactpoints move-horizontally from leftto right a set oibr ushes shown in the figure as small flat parallelograms resting upon the points of the 1st,.12th, 23d and 34th vertical sets of points. A controlling magnet or clutch magnet 209 has an armature-dog adapted to Y. engage a notched disk when not attracted, the notched clutch disk being provided with driving means to turn it in the direction indicated by-the arrow when the disk is not engagedbythe'dog, and the armature-dog being adapted to restrainthe disk when the twoparts. are engaged. The disk is attached to the brushes ofthe cylinder switch. When the clutch magnet is charged by current through its helix, its armature is withdrawn to like parts throughfrom the disk and the disk is permitted to revolve, carrying with it thebrushes of the associated switch. The disk, and therefore the brushes of the switch, may stop only in position corresponding to notches in the periphery of the disk, and these notches therefore represent the only possible stop positions of the brushes of the switch.

In the primary connector of Fig. I, the stop positions are all in the first quadrant of revolution, as indicated by the location of the eleven notches in the clutch disk. In the pilot clutch, whose magnet is 205 of Fig. 4, there are three stop pofitions required for the functions of the switch required by my invention; other stop positions may exist as required for the further functions of the switch. In the division starterof Fig. 3, the notches are located to stop the brushes" only upon contacts 4, 8, I2 and so on.

In referring to a point in a bank of contacts, mention is madefirst to the number, of its set or vertical row, counting from the left of the figure, and then of its level or horizontal row counting from the top of the bank. Thus, in Fig. plus battry is can:

nected to the pointw ichis found in the 23d vertical set from the left and the are horizontal row from the top; that'is, plus battery is connected to point 23X3Z The register is illustrated at the top of Fig. 4. The arcs of small circles represent rows of fixed contact points, upon which move the brushes shownas small rectangles upon the No. 0" set of the points: "The brushes are carried by the ratchet, which is under spring tensionagainst its pa11et,-'and is permitted to move step-by-stepnnder control of the regi ster' magnet 261. This" -1"egis-- ter complete is carried by the mechanism carrying the cylinder brushes,"to which its parts are wired. It is restored to'normal position, after having been operated, by mechanical devices which restore it during the second quadrant of revolution of the clutch disk. The cylinder switches ofthe division starter of Fig. 3 and the pilot switch-of Fig. 4 do not have registers associated with them.

The operation of the register of Fig; 4 is as follows: When themagnet 261 is charged, the pallet" 206 attached to the magnet 's; armature has its'upper tooth drawn out of engagement with its ratchet 208 and its lower tooth advanced into the-path of the ratchet teeth; the spacing'of the ratchet'teetlr and the pallet teeth is" such that the ratchet advances through an angle-equal to about-half the angle between successiveteethg'upon the' discharge of the magnetiZGI the pallet resumes its initial position, withdrawing its lower and advancing-it"s upper' tooth, per"- mitting the ratchet208 t'cstep the'remainder ofthe full tooth distance. When the ratchet 208 is at any half-step position (magnet 261 termediate between contact points and not in electrical connection with any contact point. When the ratchet 208 is at normal or any full-step position (magnet 261 discharged) the brushes rest upon one of the sets of contacts.

In the contact bank of the register of Fig. &, the first set (the normal set or the No. 0 set) of points has two vacant points, the third point, shown as the bottom point, being connected by wire 125 to the cylinder brush shown in normal position on cylinder point 23x6. The points of the No. 0 set are connected? to cylinder brushes on points 1XIO,1X11, 1X12, by wires I26, 127 129, this set of brushes being the No. 0 set of brushes, and these register points, wires and cylinder brushes being concerned in connections with lines which have the character 0""as the tens character of their directory'nlnnb'ers. The next nine sets of register points are analogously connected, each setto its corresponding set of cylinder brushes, the third or guard conductor albnebeing shown in the figure.

Of the twelve points in the bottom level of the register, ten correspond to the ten possiblecharacters of the tens place of the directory number of a calling telephone line; these ten are connected to brushes in the cylinder which, when the cylinder is in normal position, as shown in the figure, rest upon cylinder points 1X12, 1X9, 1X6 12X12', 12x9, 23x12, 23x9, 34x12, 34X9, 34X6 respectively, which are connected to wires 1 2-, 4', 5 6, 7 8', 9, respectively, in the cable 144; The c'ahle 14.4- is the decima'l cable andi extends from the relay rack of Fig. I to homologous points upon all primary" connectors serving the lines, a separate d'e'cimal cable foreach 100 lines, and ten linesserved by each wire of the cable;

In Fig. 4, 211' is'the units searching relay; 21 2 is the: searching guard relay; 269 is a portion of the bank of contacts of the pilot switch, withbridging brushes shown in the No. 2'position. The clutch magnet is 205, and its clutch disk is'cut to' stop the brushes on the No; 1 set of points, the No. 2 set of points (as sh own) or the No. 3" set of points.

The first point in the bottom level of the register, the point upon which the register brush normally rests (as'shown) is connected through wire 125, cylinder point 23X.6 wire 1'58, pilot points 2X 1" and 2, (when the pilot brushes are on theNo. 2 set of points), to wire 1'59, which wire I59 passes to the relay rack of Fig. I and terminates at the 100 front contact points of the 100 right- I hand armatures ofthe 100 line relays serv-' ing the 100 linesof the group served by the primary connector.-

In Fig. lfthe' 1 00 lines have'each two relays,-as=shown-for line 7l-8=,the upper relay 2 218 being the line or signalingfrelay for calling, and the lower relay 219 being the cut-ofi' relay for disabling the line relay and for relieving the line conductors of the call- -ing mechanism. With. the line idle, both relays are discharged, the helix of relay 219 is from ground or minus battery; to the guard wire-of the line, and thehelix of relay 218 is from plus battery through closed back contacts of relay 219 to both conductors of the line. WVhen the line is grounded, the line relay 218 is charged.

When charged, the left-hand armature of relay 218 of any line connects the first conductor of its line to wire 160 and through helix of relay 224 to earth or minus battery. Relays 224 and 225 are of low resistance, the relay 225 being adjusted to pull up its armaturequickly and release it with delay, as will be described in its operation.

When charged, the right-hand armature of the relay 218 of any lineremoves from the decimal wire of its line the earth connection normally existing through .bus wire .183, and connects the register starter wire 159 to earth through wire 183 and the helix of relay 225. 7

Normally, each wire of the cable 144 is connected through the closed back contacts of ten line relays (as 218) to the helix of relay 225 and to earth; the ten contacts of wires and 1 are shown in Fig. 1, through the contacts of the line relays of lines 700 to 709 and lines 710 to 711, respectively, and

the other decimal wires are similarly con-- nected'. The ten decimal wires thus normally place the ground of-the helix'of re lay 225 upon, the ten directory number points of the decimal register-of the primary connector of Fig. 4and upon the register of every primary connector in normal position, and upon the cylinder points of every primary register. The normal point of the register is normally ungrounded. .The action of any calling line is to ground the normal point of the register and to remove the ground from that register point corresponding to the tens digit of the calling line, this action being effected by the movement of the right-hand armature of the charged line relay, as 218.

The primary connector cylinder brushes being in normal position, the register brush 217 cannot remain upon a grounded point. r Ground being placed experimentally upon wire 159, current flows from-plus battery on primary cylinder point23X3,'brush in normal position, helix of register magnet261, brush 217, normal oint of register, wire 125, brush in norma position, point 23X6, wire 158, pilot point 2X1, pilot brushes stopped on No. 2 set of points, point 2X2, to wire 159 and to the experimental ground; Magnet 261 is charged, its armature responds, pallet 206 moves, and ratchet 208 as 'hereinbefore described moves the register brushes to the half-step position, breaking the connection of brush 217 from its normal point.

charged, its armature is released, pallet 206 returns to its normal position, ratchet 208 makes its complementary step, brush 217 advances into engagement with its point in the N o. 0 set of register points.

By advancing to its No. 0 position, brush 217 has closed a path for current through magnet 261, as follows: From plus battery on primary cylinder point 23X3, brush in normal position, helix of register magnet 261, brush 217, 3d register point of No. 0 set, Wire-161, brush in normal position, point 1X12,'wire 162, wire 0 of cable 144, (to Fig. 1), through ten closed back contacts and armatures of ten line relays of ten lines. 700-to-709 inclusive, wire 183, helix of relay 225 to minus battery. Relay 225 is charged but effects nothing' Magnet 261 is charged, register brush 217 advances to its half-step position.

By advancing to its half-step position, brush 217' has interrupted the current through magnet 261. Magnet 261 is discharged and brush 217 advances into engagement' with its point in the No. 1 set of register points.

By advancing to its N o. 1 position, brush 217 .closes the path from point 23X3 through helix of magnet 261, brush 217,

point of N o. 1 set, wire 163, point 1X9, wire 164, wire 10f cable 144, (to Fig. 1), closed contacts oflines 710-to-719, wire 183 and helix of relay 225. Current over this path charges 261, which breaks the charging circuit at 217, which again closes a charging circuit through its No. 3 point, to be broken as before, and so continuously until brush 217 has passed its No. 9 point, when it will come to rest upon its last point, beyond the last decimal wire. With the brush 217 thus advanced beyond the last decimal wire,

brush 215 rests upon point 220, and current flows over a path as follows: from plus pole of battery 200, helix of pilot clutch magnet 205, wire 105, pilot point 2X8, pilot brushes stopped on No. 2 set of points, point 2X7, wires {165 and 166, primary point 12X4, cylinder brush in normal posi tion, register brush 215, register point 220, wire 167, cylinder brush in normal position, cylinder poin't 34X6, wire 168, Wire 9 of cable 144, closed contacts of line relays of lines 790-to-799 inclusive, wire-1S3 helix of relay 225 to minus battery. Pilot clutch magnet 205 is charged and the pilot brushes leave their No. 2 set of points. The pilot switch completes its cycle; in so doing, it

revolves the cylinder brushes of the primary connector and 1 thus restores the brushes of" the primary connectorsdecimal register.

To adjust the decimal register to any de sired position, the earth connectionis removed from the decimal wireof the position-inwhich it is desired thatthe brushesof the register should stop and'ground is applied to the wire 125; the register brush 217 immediately moves into engagement- My improved division starter is shown in Fig. 3 with three sets of cooperating pilot points, a fourth set of pilotpoints being found-in-points 1X11X12 and 2X11X12 of the pilot bank 269 of Fig. 4:. The division starter itself comprises the contact bank 234,- of- .two horizontal rows of points, with One pair of bridged brushes shown on points No. 4:, together with the clutch mechanism having the clutch 1 magnet 253, and the relay252. One omnibus wire 120 extendsi-to' point 2X11 onallpilot switches,: and a;wire 119, individualto each'pilotswitch extendsfrom pilot-pointv 1X11 to a pair of points in the division starter.

The helix of the starter clutch magnet is connected from: plus -to minusbattery through the back contact of starter relay 252, so that .when starter'relay 252..is-dis charged the starter brushes will movecon tinuously. The helix of starter .relay is connected fromplus: battery to bus'.wire 120,

passing-t0 all pilot'points 2X11, all pilot points 2X12 being connected tominusbattery and pilot brushes being arranged to close 2X11 to 2X12 when theset of pilot-- brushesare-upon their No. 2 set of points; thus starter relay 252is charged when any pilot switch is upon its No. 2 .set of points,

and only When some pilot switch is uponv its No. '2 .set of pointsare the bridgedbrushesof :the starter at rest.

The operation of the starter-in service'is as follows: In'the conditions of the figures,

it is held motionless .by the charging of relay 252 over-the path through the pilot switch of Fig. 4, whose brushes are at rest. When the, brushes of the-pilot of Fig. 4,-taken-as the: first connective division of'the' group. of connective divisions served by the starter of upon the No.-2..-set of contacts.

Fig. 3, leave their No.2: stop position, .in

the promotion of atelephone :call or for any.

reason, the circuit between pilot points 2X11 and 12 of Fig.4 is broken,.the path through the helix of. starter relay .252 is broken, the. 6& armature of starter relay 252 is: released, and

starter clutch magnet 253'is charged. Starterbrushes leave their-No. 4: points and engage their No. 5 points. The pilot switch of the second connective division being normal,-

current flows from plus battery. through: pilot clutch magnet 205'2, closed pilot-- points, wire =1192 and starter points No. 5 to minus battery; 2052'is charged and pilot-brushes move,

reachingtheir second set'of points at about the. time that starter brushes reach points No. 6. The pilot brushes stop ontheir second set of points, closing a path for current from plus battery through helix of starter relay='252, wire 120, closed pilot tionintthe division, starter relay 252 would not have been charged, and the starter brushes would nowmove continuously until points No. 9 were engaged, when the clutch magnet 205%3 of the next' division, orof' the first idle division would have been charged and by current over a path closed by the starter-brushes, and the pilot brushes of thez-idle' division would have moved totheir N o. 2 set-of points to charge the starter relay 252-to stoprthestarter-brushs to prevent the starting of further pilot switches until the connective-division thus selected and thus set of]? normal should .have'been advanced further than its No. 2 set of points by some means other than the starter control.

With reference to the-starter, the connective divisions-have three conditions, as evidenced and distinguished bythe-positions of their "v pilot switch brushes. (a) The pilot switchmay be-idle, awaitingse lection by the starter, in which condition its pilot-brushes are upon their No. 1 set of points, and path is closed through from plus batterytothe starter points. (1)) The pilot'switchamay be-awaiting a call. from Pilot clutch magneta telephone line, having been selectedby the 'starterto serve the-next call, in which con-v dition: its pilot brushes areupon their No.

2 set of points and are'holding the starter relay 2 52 charged, preventingothe starter from advancing any other pilot switch to av similar condition: .(c) The pilot switch and. its division may be promoting,

sustaining: or disrupting -a connection, in

which. condition 1.: its pilotr brushes .are Y not;

sistance relay 224 to earth.

that by connecting the right-hand back conuponeither the N0. 1- or No. 2 set of points and the starter and division are mutually independent. The starter relay 252 is adapted to sustain continuous current from the battery 200.

The requirement of the system of my invention with reference to the telephone substation'equipment is that within that equipment sucha change shall bepossible as to effect the charging of the line relay, as 218, of the telephone line. The central ofiice ground connection required in the figures upon the first conductor of the calling line, as upon wire 121 of line No. 705, issupplied by the line relay when charged, by connecting the first conductor of theline through the left-hand armature of the line relay to wire 160 and through the helix of low-re- It is obvious tact of relay 219 to minus battery instead of to the helixof- 218, the liftingofthe receiver at the telephone .substantion would provide the required condition; SeeFig. 5.

The operation of the systemof my in- V vention is as follows: A telephone user, to

call from the station as that shown in Fig.

'2, manually advances the arm242 into engagement with'the point 244. This station is upon line 705., Current flows and charges relay 226 over the following path: plus sign, helix-of relay 226, wire 191, wire 121 o (to Fig. 2), arm 242, point 244, to earth or minus battery. Relay. 226 being charged, current flows and charges relay 224 over the following path: from plus sign, helix of relay 226, armature and front contact (now closed) of relay 226, wire 160, helix of relay 224, to minus sign or minus battery.

Relay 226 being charged, current flows also downward to wire 183 and through helix of relay 225 to minus battery.- Relay 225 also is charged. The register of Fig. 4 now operates as described and, stops on the No. 0 set of points, corresponding to the tens digit of the line No. 705. During this operation, relay 225' has had its armature attracted but now releases it, and current flows to charge primary connector clutch magnet over the following path: from plus sign, helix ofclutch ma et 209, wire 110, pilot points 2X3 and 4, wire 184, back contact and armature of relay 211, wire 185, (to Fig. 3-) back contact and armature of relay 225, armature and front contact (now closed) of relay 224, to minus battery, I 7

By the charging of the clutch magnet 209,

the primary connector brushes are driven over the contacts of the cylinder until line 7 05. is found, when searching relay 211 is charged by current over the following path: from plus sign, helix of relay 211, armature and back contact of relay 212, wire 186, pilot points 2X6 and 5, wire 111, brush six points off normal, on point 18X4, register brush 215, registerpointof No. 0 set of points, wire 126, brush six points off normal on cylinder point 7X10, wire 121, (to Fig. 1), wire 191, left-hand armature and contact (now closed) of relay 226, wire 160, helix of relay 224, to minus battery.

v By the 'chargingof relay 211, the clutch magnet 209 is discharged and the brushes of the primary connector stop on line No. 705.

Had line No. 7 04 been busy, then when the brushes engaged that line, in their progress toward line 705, relay 212 would have been charged by current over the following path: from plus battery upon primary connector cylinder point 6X12, guarding the busy line 7 04, wire 161, bottom point of register set N o. 0, brush on cylinder point 17X6, wire 113, pilot points 2X9and 10, helix of relay 212 to minus battery. Relay 212 being charged, the circuit of the helix of relay 211 is opened, preventing the seizure of the busy line 7 04 by the searching primary co nector.

I, The plus battery upon primary connector cylinder point 6X12 mentioned in the paragraph above as guarding the busy line 704, exists upon that point because the line 704 'while guarded, is connected with some connectlvedivlslon or primary connector other than the testing and operating division above considered and the plus battery upon that point is obtained through this other division from plus battery upon pilot switch point 3X10 over. brushes on the No. 3' points to pilot point 3X9, wire 113, brush 217, wire 161 and ,brush on 12th level adjusted upon point 12X6 to connect with line 704. The

circuit, having extended from plus battery thus far through ,the said other division, passes through the multiple line wire to testing division and thence continues, over the circuit traced in the paragraph above.

By the charging of relay 211, theclutch magnet 205 of the pilot switch is charged by current over the following path: from plus sign on main battery 200, helix of clutch magnet 205, wire 105, pilot points 2X8 and 7, wire 165, front contact and armature (now attracted) of relay 211, wire 185, (to Fig. 2), back contact and armature of relay 225, armature and front contact (now closed) of relay 224, to minus-battery.

By the charging of the clutch magnet 205, the pilot switch brushes move, stopping in their third stop position, on contact set N o. 3. In this position, plus battery is connected through pilot points 3X10 and 9 to wire 113 and to the guard wire of line 705, the cutoff relay of that line being charged by current over the following path; from plus sign,

pilot points 3X10 and 9, wire 113, primary connector cylinder point 18X6, cylinder brush six points ofi normal, brush 217, wire 161, wire 123, (to Fig. 1), wire 193, helix of cut-off relay 227 to minus battery. The charging of the relay 227 discharges relay 226. The discharge of relay 226 discharges relay 224.

The departure of the pilot brushes from the No; 2 set of points discharges relay 252 of Fig. 3 and the division starter operates to select an idle pilot switch, which it advances to the second set of points in readiness to serve the next call.

The subsequent operations of the connection in response to the call thus received and assigned to a connective division may be in accordance with the general practice in exchanges of the Lorimer type of apparatus.

What I claim is:

1. In an automatic telephone system, a selecting switch of two movements of selection; two sets of indicator conductors, each set indicating stop positions in one movement of selection; a line having eligible points in said switch; a relay pertaining to said line and controlling circuits of two Wires one in each of said sets, said two wires thus controlled determining the position of the said switch for the selection of the said points of said line, a series of circuits for moving said switch in its first movement of selection, and a relay in series with all of said circuits of said series and controlling said switch to move in its second movement of selection.

'2. In an automatic telephone system, a selecting switch of two movements of selection; two sets of indicator conductors each set indicating stop positions in one movement of selection; a plurality of relays each controlling a conductor in each set; a circuit for moving the switch in its first movement and for stopping it in that movement in the stop position indicated by the conductor of a charged one of said relays, and a slow acting relay in said circuit and in series with the switch-driving means of the circuit and acting after said switch-driving means has ceased operating, said slow relay controlling the starting of the said switch in its second direction of movement.

3. In an automatic telephone system, a selecting switch of two movements of selection; two sets of indicator conductors each set indicating stop positions in one moveselection; means for'accomplishing the a movement to the indicated plishing the second movement, said ing to close the path through some n ment of selection; means for changing; electrical status of one conductor of set; and means for moving the switch two movements and for stopping it im movement in the stop position indica the changed conductor, a 'pluralit he! cuits-used successively in propel" switch in its first movement of selectionl a relay in series with all of said circ'ui acting to start the switch in its second ment of selection only after its first ment of selection has been accompli 4. In an automatic telephone sy H selecting switch having two movemett selection; means for indicating within switch a stop position in each movemenfi p fit means subsequently operable folfor accomplishing the second movement v prising in part, a slow acting relay w:- is included in series with said means inseam coinplishing the first movement.

5. In an' automatic telephone switch, selecting brush; contact points for brush; a driving means for said bruslmcircuit including the brush and its L" and when closed, controlling said dri means to move the brush; normally paths from said points except the point; means for closing the path t the normal point and for opening the a of another point, and a slow relayin with all of said closed paths, said relay crating to close its controlled circuit a when no current flows through any of :v paths.

6. In an automatic telephone switclt, selecting brush; contact points for brush; a driving means for said brush g circuit including the brush and its contlan and when closed controlling said dri means to move the brush; normally e paths from said points except the ii point; a line; points in said switch and. taining to said line; a relay pertain said line, said relay when charged 0 point and open the path of another and a slow relay in series with all 0 i closed paths and acting to close this only after current has ceased through? and all of said closed paths for a p mined period.

7 In an automatic telephone swi selecting brush; contact points for brush; a driving means for said brush circuit including the brush and its in and when closed controlling said u means to move the brush; normally paths from said points except'the point; a line; points in said switch 8* pertaining to saidline; a relay pe m to said line, said relay when charged l ating to close the path through some normal point and onen the path of another point;

tion, a relay in series in said circuit and 15 holding its armature attracted during the motion of said switch in the first movement of selection; and a second electric circuit controlling the motion of said switch in the second movement of selection and itself controlled in part by said relay.

Signed by me at Toronto, county of York, and Province of Ontario, Canada, in the presence of two witnesses.

DAVID S. HULFISH. Witnesses D. S. TovELL, l/VM. J. HERDMAN.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C. 

